PSG CADDY Installation And Operating Instructions Manual page 7

You must determine the air flow through the existing furnace before installing the
Caddy add-on:
1. Run the oil furnace for at least 15 minutes, or until it reaches its maximum
temperature.
2. With a thermometer, measure the temperature of the cold air entering the furnace
and that of the air exiting the furnace in the hot air plenum.
The temperature rise is obtained by subtracting the cold air return temperature from
that of the air exiting in the hot air plenum..
3. Make the following verifications (OIL):
CFM = orifice size (SI)(liter/hour) x 39 023 x E
CFM = orifice size (Imperial)(gallon/hour) x 140 000 x E
E : Average heat generator efficiency (0.75)
T : Temperature rise (ºC)
4. After the installation of the add-on, the original numbers must be restored in order
to maintain a constant air flow through the furnace.
1.21 x T
1.1 x T
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